Apparatus for clarifying contaminated fluids

ABSTRACT

An apparatus for clarifying a contaminated fluid mixture containing contaminating fluid, principal liquid and solids, comprising a vertically standing cylindrical vessel for separating the contaminants from the principal liquid; a preliminary separator for tangentially introducing the contaminated fluid into the vessel; sparging tubes to aerate the contaminated fluid mixture, thereby separating the contaminating fluid from the principal liquid and solids; and a reservoir for collecting the contaminating fluid. The reservoir and preliminary separator are located in the upper portion of the vessel. The sparging tubes are located in the lower portion of the vessel.

This application is a continuation-in-part application of a previousapplication by the same inventor bearing U.S. Ser. No. 08/444,908 filedMay 18, 1995, now U.S. Pat. No. 5,522,999, which is a divisionalapplication of U.S. Ser. No. 08/359,406 filed Dec. 20, 1994, now U.S.Pat. No. 5,492,622 issued Feb. 20, 1996, which is a continuation-in-partapplication of U.S. Ser. No. 08/179,042 filed Jan. 7, 1994, now U.S.Pat. No. 5,376,266 issued Dec. 27, 1994, which is a continuation-in-partapplication of U.S. Ser. No. 08/123,231 filed Sep. 20, 1993, now U.S.Pat. No. 5,407,584 issued Apr. 18, 1995, which is a continuation in partapplication of U.S. Ser. No. 08/026,877 filed Mar. 8, 1993, now U.S.Pat. No. 5,300,222 issued Apr. 5, 1994, which is a continuation-in-partapplication of U.S. Ser. No. 07/965,888 filed Oct. 23, 1992, now U.S.Pat. No. 5,277,803 issued Jan. 11, 1994, which is a continuationapplication of U.S. Ser. No. 07/589,471 filed Sep. 28, 1990, now U.S.Pat. No. 5,158,678 issued Oct. 27, 1992. The entire previousapplications are incorporated herein by reference as if set forth infull below.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus and method for separatingthe contaminants from a contaminated fluid mixture, particularly anapparatus and method for separating oil and other contaminants fromwater in a contaminated mixture.

2. General Background

Clean water is becoming scarce due to its wide use in many industries,including the oil and gas industry, and in pulp and paper mills,municipal waste treatment facilities, steel mills, food processingplants and electric generating plants. Polluted water, containingcontaminating fluids, such as oil, and solid contaminants, is aby-product and ever-growing problem of these industries. In particular,the production of oil and gas wells and the refinement of these fluidsproduces contaminated wastewater. A need exists to clarify and recoverthe water from the contaminated wastewater.

Several devices have been proposed for recovering the water byclarifying and/or separating out the contaminants from the wastewater.

U.S. Pat. Nos. 5,407,584 and 5,300,222, both issued to applicant'sassignee, and entitled "Water Clarification Method" and "WaterClarification Method And Apparatus", respectively, teach a method andapparatus for separating oil-gas vapors and solids from a liquid whichhas a separator vessel with a cyclonic flow chamber and a tangentialinlet with a spiral preliminary separator to introduce the fluid andestablish a swirling body of fluid. The cyclonic flow chamber hasconcentric shells positioned below the tangential inlet for dischargingseparated solids and further separating oil and water. The cyclonic flowchamber and the separator vessel wall form a fluid flow zone whereeductors aerate the water and oil mixture, thereby separating them. Avertical outlet port discharges separated oil and gas from the upperportion of the cyclonic flow chamber to a fluid flow zone wherein theoil and gas are separated. The separated water, oil, gas and solids areremoved through discharge ports in the separator vessel.

U.S. Pat. No. 4,731,164 issued to W. R. WILLIAMSON and entitled"Multi-Stage Flash Evaporator" discloses a multi-flash evaporatorwherein the fluid to be flashed is tangentially fed to each stagethrough an inlet which enters each stage about the midpoint of eachstage.

The aforediscussed U.S. Pat. Nos. 5,407,584 and 5,300,222 are somewhatcomplex in design, having multiple separation stages with the separationmethod separating different contaminants at different stages.

The aforediscussed U.S. Pat. No. 4,731,164 is concerned with separatingcontaminated fluids through heat, not physical separation throughturbulence.

Thus, a need exists for an apparatus and method for removing oil andsolids from contaminated water which is simple in design, requiringfewer parts and/or stages than the prior art devices.

A need also exists for an apparatus and method with the above featuresthat accomplish the above stated separation in one stage or fluid flowarea.

SUMMARY OF THE PRESENT INVENTION

The preferred embodiment of the apparatus of the present inventionsolves the aforementioned problems in a straight forward and simplemanner. What is provided is an apparatus and a method for clarifying acontaminated fluid mixture, such as oily water, containing water,contaminating solids and contaminating fluids. The apparatus comprises avertically standing cylindrical vessel for separating the contaminantsfrom the principal liquid; means for tangentially introducing thecontaminated fluid mixture into the vessel so as to establish a swirlingbody of fluid therein; aeration means for introducing air or othergases, in the form of micro-fine bubbles, into the contaminated fluid inthe vessel such that the swirling motion of the fluid causes the bubblesto rise to the surface of the contaminated fluid mixture, entrapping andseparating the contaminating fluid from the principal liquid and solidsin the contaminated fluid mixture; and, a reservoir or container forcollecting the contaminating fluid floating on the surface of thecontaminated fluid mixture, the container being located in the upperportion of the vessel. The introducing means extends into the upperportion of the vessel, below the top of the container. The aerationmeans extends into the lower portion of the vessel.

The method of the present invention comprises introducing a contaminatedfluid mixture containing water, contaminating solids and contaminatingfluids into a preliminary separation means for producing bubbles in thecontaminated fluid mixture to entrap and separate the contaminatingfluids from the principal liquid and solids in the contaminated fluidmixture; tangentially introducing the contaminated fluid mixture fromsaid preliminary separation means into a vertically standing cylindricalvessel in a circular motion such that the contaminating fluid willfurther separate from the principal liquid and solids, and rise to thesurface of the swirling fluid mixture; introducing air in the form ofmicro-fine gas bubbles into the middle of the swirling fluid mixturesuch that the micro-fine bubbles rise to the surface of the fluid,further entrapping and separating the contaminating fluid from theprincipal liquid and solids in the contaminated fluid mixture;maintaining the circular flow of the contaminated fluid within thevessel such that the fluid separates out into contaminating fluid on thesurface of the fluid mixture, clean liquid in the middle of the fluidmixture, and solid contaminants at the bottom of the fluid mixture whichsettle to the bottom of the vessel; collecting the contaminating fluidon the surface of the contaminated fluid in a container by controllingthe level of the contaminated fluid mixture in the vessel; anddischarging the clean liquid through a discharge port provided in thelower portion of the vessel.

In view of the above, it is an object of the present invention toprovide an apparatus and method for removing oil and solids from waterwhich is simple in design, requiring fewer parts and/or stages than theprior art devices.

It is a further object of the present invention to provide such anapparatus and method with the above features that accomplishes the abovestated separation in one stage or fluid flow area.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature and objects of the presentinvention, reference should be had to the following description taken inconjunction with the accompanying drawings in which like parts are givenlike reference numerals and, wherein:

FIG. 1 is a side view of the preferred embodiment of the apparatus ofthe present invention with some interior features shown in phantomlines;

FIG. 2 is a cross-sectional view of the embodiment of FIG. 1 taken alongLines 2--2 of FIG. 1, and, further, illustrating the method of thepresent invention; and

FIG. 3 is a cross-sectional view of the embodiment of FIG. 1 taken alongLines 3--3 and, further, illustrating the method of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawing, and in particular FIG. 1, the apparatus ofthe present invention is designated generally by the numeral 10.Apparatus 10 clarifies contaminated fluid mixtures, such as oily water,by separating contaminating fluids, such as oil, and solid contaminants,from the principal liquid, such as water. Apparatus 10 is generallycomprised of vertically standing cylindrical vessel 12 for separatingtherein the contaminants from the contaminated mixture, introducingmeans 14 for tangentially introducing the contaminated fluid mixtureinto vessel 12, oil reservoir or container 16 for collectingcontaminating fluid (oil) from the contaminated fluid mixture and means18 for aerating the contaminated fluid mixture and further separatingthe contaminating fluid from the principal liquid and solids in thecontaminated fluid mixture.

Vessel 12 has outlets 38 and 48 for discharging contaminated fluid andseparated principal liquid, respectively. Waste oil discharge outlet 38is located in the upper portion of vessel 12 and lower portion ofreservoir 16 and removes oily liquid from reservoir 16. Clean liquidoutlet 48 is located in the lower portion of vessel 12. Discharge piping52 is located in the bottom of vessel 12 for discharging solidcontaminants after they settle to the bottom of vessel 12. Vessel 12 ismounted on support 50. Discharge piping 52 extends downwardly fromvessel 12, turns ninety (90°) degrees via elbow 54 and exits fromsupport 50 to connect to piping (not shown) via outlet port 56.

Manways 60 and 62 are located in the top and in the lower portion,respectively, of vessel 12 to allow access for maintenance and repair.Vessel 12 can be a pressurized vessel or an atmospheric vessel. Vessel12 is preferably as vertically elongated as possible to provide morespace for separation of the contaminating fluid from the principalliquid.

Introducing means 14 extends into the upper portion of vessel 12,preferably about 1 foot below surface S of contaminated fluid mixture Ffrom a source (not shown), as best seen in FIG. 2. Introducing means 14includes inlet T-section 22, inlet port 24 mounted on T-section 22 foraccepting the contaminated fluid mixture F, and vessel inlet 20 which isconnected on one end to T-section 22 and sealingly mounted on the otherend to vessel 12 to transport the contaminated fluid mixture F intovessel 12. Introducing means 14 also includes inlet pipe 25 which isconnected to inlet 20 at its proximate end and, extends horizontallyinto vertical vessel 12 turning substantially ninety (90°) degrees (awayfrom wall 34 of reservoir 16) via elbow 26 at its distal end to contourto the shape of the interior wall of vessel 12, as best seen in FIG. 3.The curved shape of this distal end portion of pipe 25 contributes tothe circular flow (ARROWS E) of the contaminated fluid mixture F invessel 12. Introducing means 14 also includes preliminary separationmeans 21 for producing turbulence and bubbles (not shown) in theincoming contaminated fluid mixture F such that the bubbles trap andseparate the contaminating fluid from the liquid and solids in thecontaminated fluid mixture F, as best seen in FIG. 3. Preferably,preliminary separation means 21 is a sparging tube mounted in T-section22 and extending through inlet 20 into the proximate portion of pipe 25.Introducing means 14 also includes restrictor orifice 28 mounted at thedistal end of pipe 25 to increase the velocity of the contaminated fluidmixture F as it enters vessel 12, as best seen in FIGS. 2 and 3. Thisincreased velocity due to orifice 28 contributes to the circular flow(ARROWS E) of the contaminated fluid mixture F in vessel 12, as bestseen in FIG. 3.

Oil reservoir or container or waste bucket 16 is mounted interiorly ofand in the upper portion of vessel 12 such that pipe 25 of introducingmeans 14 is positioned horizontally adjacent the midpoint of container16. Wall portion 30 of vessel 12, spaced vertical plate 34 and angulatedplate 32 together form container 16, as best seen in FIG. 2. Wastedischarge outlet 38 is located in wall portion 30, near the bottom ofcontainer 16. The top edge 35 of vertical plate 34 has a weir 36, bestseen in FIG. 1, which selectively allows contaminating fluid to spillover into container 16. Contaminating fluid is removed from container 16through waste discharge outlet 38, as best seen in FIG. 2.

Aerating means or eductors 18 extend into the lower portion of vessel12, above clean liquid outlet 48. Eductors 18 preferably extendhorizontally into vessel 12 about one and one-half (11/2) feet aboveoutlet 48. Eductors 18 provide air to vessel 12 from a source of air(not shown) through gas head feeders 40, which are connected to pipes 44via air inlets 42, as best seen in FIG. 3. Inlets 42 are sealinglyconnected to vessel 12. Sparging tubes 46, which have smaller diametersthan pipes 44, are mounted to pipes 44 and extend horizontally intovessel 12. Sparging tubes 46 introduce air in the form of micro-fine gasbubbles M into contaminated fluid mixture F in vessel 12, as best seenin FIG. 2. These micro-fine bubbles M further entrap and separate thecontaminating fluid from the principal liquid and solids in thecontaminated fluid mixture F in vessel 12.

Referring now to FIGS. 2 and 3, the method of the present invention isbest illustrated. Contaminated fluid mixture F, such as oily water,containing contaminating fluids, such as oil, and solid contaminants,and a principal liquid, such as water, is introduced to preliminaryseparation means 21. Preliminary separation means 21 creates animmediate mixing action, producing turbulence and bubbles (not shown) inthe contaminated fluid mixture F. These bubbles entrap and separate thecontaminating fluid from the principal liquid and solids in thecontaminated fluid mixture F. The contaminated fluid mixture then flowsthrough vessel inlet 20 and pipe 25, as indicated by ARROW X in FIG. 2and ARROW D in FIG. 3, and is tangentially introduced to vessel 12 atPOINT p. Pipe 25 is curved ninety (90°) degrees, via elbow 26, tocontour the shape of vessel 12, thereby creating a circular flow ofcontaminated fluid mixture F in vessel 12, as indicated by ARROWS E inFIGS. 2 and 3. Restrictor orifice 28 increases the velocity of thecontaminated fluid mixture F entering vessel 12, thereby improving thecircular flow of contaminated fluid mixture F in vessel 12, as best seenin FIG. 2.

Upon introduction of the contaminated fluid to vessel 12, sparging tubes46 of eductors 18 introduce air, in the form of micro-fine gas bubbles Minto contaminated fluid mixture F to further entrap and separate thecontaminating fluid from the principal liquid and solids in thecontaminated fluid mixture F, as indicated by ARROWS Y in FIG. 3. Themicro-fine bubbles M are introduced in the lower portion of vessel 12above clean liquid outlet 48, to increase the amount of contaminatingfluid entrapped and separated.

Contaminated fluid mixture F is maintained in a circular flow aroundvessel 12 such that the contaminating fluid separates from the principalliquid and solids and rises to surface S of contaminated fluid mixtureF, as best seen in FIG. 2, and the solids separate from the liquid andsettle to the bottom of vessel 12 (collected solids Z in FIG. 2),leaving clean principal liquid (water) in the middle portion of vessel12.

The circular flow of contaminated fluid mixture F is maintained suchthat the level of the fluid mixture F remains around the height of weir36 of container 16, as best seen in FIG. 2. The separated contaminatingfluid on surface S of contaminating fluid mixture F spills over weir 36and is collected in container 16, as indicated by ARROW B in FIG. 2.Contaminating fluid W (principally oil) is then drained from container16 through waste discharge outlet 38, as indicated by ARROW C in FIG. 2.

The clean liquid (substantially water) is discharged through cleanliquid outlet 48 provided in the lower portion of vessel 12, asindicated by ARROW 0 in FIG. 3, and collected solids Z are removed fromvessel 12 through discharge pipe 52.

In operation, a contaminated fluid mixture F containing oil, water, andsolids is introduced to apparatus 10 through inlet port 24 ofintroducing means 14. The mixture F enters T-section 22, where itcontacts sparging tube 21. Sparging tube 21 creates an immediate mixingaction, producing turbulence and bubbles (not shown) in the mixture F.These bubbles trap and separate the oil from the water and solids in themixture F (oily water). The mixture F then flows through vessel inlet 20and pipe 25, as indicated by ARROW X and ARROWS D, in FIGS. 2 and 3,respectively, and is tangentially introduced to vessel 12 at POINT P.Pipe 25 is curved ninety (90°) degrees, via elbow 26, to contour to theshape of vessel 12, thereby creating a circular flow of fluid mixture F(oily water) in vessel 12, as indicated by ARROWS E in FIGS. 2 and 3.Restrictor orifice 28 increases the velocity of the fluid mixture Fentering vessel 12, thereby improving the circular flow of the mixture Fin vessel 12.

Upon introduction of fluid mixture F (oily water) into vessel 12,sparging tubes 46 of eductors 18 introduce air in the form of micro-finegas bubbles M into the oily water to further entrap and separate the oilfrom the water and solids in the oily water, as indicated by ARROWS Y inFIG. 3. The micro-fine gas bubbles M are introduced in the lower portionof vessel 12 above clean liquid outlet 48, to increase the amount of oilentrapped and separated.

The oily water mixture F is maintained is a circular flow around vessel12 such that the oil separates from the water and solids and rises tosurface S of the oily water mixture F, as best seen in FIG. 2, and thesolids separate from the water and settle to the bottom of vessel 12 dueto the action of gravity, leaving clean water in the middle portion ofvessel 12.

The circular flow of the oily water mixture F is maintained such thatthe level of the oily water remains around the height of weir 36 ofcontainer 16, as best seen in FIG. 2. The separated oil on surface S ofthe oily water F spills over weir 36 and is collected in container 16,as indicated by ARROW B in FIG. 2. The oil is then drained fromcontainer 16 through waste discharge outlet 38, as indicated by ARROW Cin FIG. 2.

The clean water is discharged through clean liquid outlet 48 provided inthe lower portion of vessel 12, as indicated by ARROW 0 in FIG. 3, andthe collected solids Z are removed from vessel 12 through discharge pipe52.

As can be seen from the above description and drawing, apparatus 10 issimple in design, requiring fewer parts and/or stages than the previousdevices discussed above.

Furthermore, apparatus 10 accomplishes the separation process in onestage or fluid flow area, thus allowing apparatus 10 to clarify morecontaminated fluid than the previous devices discussed above.

Because many varying and differing embodiments may be made within thescope of the inventive concept herein taught and because manymodifications may be made in the embodiment herein detailed inaccordance with the descriptive requirement of the law, it is to beunderstood that the details herein are to be interpreted as illustrativeand not in a limiting sense.

What is claimed as invention is:
 1. An apparatus for clarifying acontaminated fluid mixture containing contaminating fluid, principalliquid and solids, the apparatus comprising:(a) a substantially verticalcylindrical vessel wherein said contaminating fluid and solids areseparated from said principal liquid in the contaminated fluid mixture;(b) means for tangentially introducing said contaminated fluid mixtureinto the upper portion of said cylindrical vessel so as to establish aswirling body of fluid therein; (c) aeration means extending into saidvessel for introducing a gas into said contaminated fluid mixture in theintermediate portion of said vessel such that the swirling motion of thecontaminated fluid mixture causes said gas to rise to an upper surfaceof said contaminated fluid mixture, thereby entrapping and separatingsaid contaminating fluid from said liquid and solids in saidcontaminated fluid mixture; and, (d) means for collecting saidcontaminating fluid which has risen above the surface of the swirlingbody of contaminated fluid mixture, said collecting means beingpositioned in the upper portion of said vessel such that the top portionthereof is positioned above said tangential introducing means, saidcollecting means comprising:i) a substantially vertical weir or wallportion spaced from said tangential introducing means and extendinglaterally in said upper portion of said vessel and defining a collectioncontainer having a generally segment shaped cross section with an opentop; ii) a bottom portion connected to said vertical wall portion andthe inside wall of said vessel, thereby forming said container open atthe top within said upper portion of said vessel; and, iii) an outletport provided in the wall of said upper portion of said vessel and inthe lower portion of said container, whereby contaminated fluid isremoved from said collecting means.
 2. The apparatus of claim 1, whereinsaid gas is introduced into the lower portion of said vessel and isintroduced in the form of micro-fine air bubbles.
 3. The apparatus ofclaim 1, wherein said tangential introducing means includes apreliminary separation means for producing gas bubbles in thecontaminated fluid mixture as it is introduced into said vessel suchthat said bubbles entrap and separate contaminating fluid from saidprincipal liquid and solids in the contaminated fluid mixture.
 4. Theapparatus of claim 3, wherein said preliminary separation means is asparging tube mounted within said tangential introducing means.
 5. Theapparatus of claim 1, wherein said tangential introducing means includesan end portion within said vessel that contours to the cylindrical shapeof said vessel to increase the circular flow of the contaminated fluidmixture entering said vessel.
 6. The apparatus of claim 1, wherein saidtangential introducing means includes a restricted orifice to increasethe velocity of the contaminated fluid mixture entering said vessel. 7.The apparatus of claim 1, wherein the tangential introducing means isprovided through said vessel below the surface level of saidcontaminated fluid.
 8. The apparatus of claim 1, wherein said aerationmeans includes a plurality of tubes which extend horizontally into saidvessel and introduce air, in the form of micro-fine bubbles, into thecontaminated fluid mixture in said vessel.
 9. The apparatus of claim 8,wherein said tubes are made of a material selected from the groupconsisting of stainless steel or co-polyvinyl chloride.
 10. Theapparatus of claim 1, wherein said weir selectively allows contaminatingfluid floating on the surface of the contaminated fluid mixture to entersaid collecting means.
 11. An apparatus for clarifying a contaminatedfluid mixture containing contaminating fluid, principal liquid andsolids, the apparatus comprising:(a) a substantially vertical elongatedcylindrical vessel wherein said contaminating fluid and solids areseparated from said principal liquid in the contaminated fluid mixture;(b) means for tangentially introducing said contaminated fluid mixtureinto said vessel so as to establish a swirling body of fluid therein,said introducing means extending into the upper portion of said vesselbelow an upper surface of said contaminated fluid; (c) aeration meansextending into the lower portion of said vessel for introducing air, inthe form of micro-fine bubbles, into the contaminated fluid in theintermediate portion of said vessel such that the swirling motion of thecontaminated fluid mixture causes said micro-fine bubbles to rise to thesurface of the contaminated fluid mixture, thereby entrapping andseparating the contaminating fluid from said principal liquid and solidsin the contaminated fluid mixture; and, (d) means for collecting saidcontaminating fluid which has risen above the surface of the swirlingbody of the contaminated fluid mixture, said collecting means beingpositioned in the upper portion of said vessel such that the top portionthereof is above said tangential introducing means, said collectingmeans comprisingi) a substantially vertical weir or wall portion spacedfrom said tangential introducing means and extending laterally in saidupper portion of said vessel and defining a collecting container havinga generally segment shaped cross section with an open top; ii) a bottomportion connected to said vertical wall portion and the inside wall ofsaid vessel, thereby forming a container open at the top within saidupper portion of said vessel; and, iii) an outlet port provided in thewall of said upper portion of said vessel and in the lower portion ofsaid container, whereby contaminated fluid is removed from saidcollecting means.
 12. The apparatus of claim 11, wherein said tangentialintroducing means includes a preliminary separation means for producinggas bubbles in the contaminated fluid mixture as it is introduced intosaid vessel such that the bubbles entrap and separate the contaminatingfluid from said principal liquid and solids in the contaminated fluid.13. The apparatus of claim 12, wherein said preliminary separation meansis a sparging tube mounted within said tangential introducing means. 14.The apparatus of claim 11, wherein said tangential introducing meansincludes an end portion within said vessel that contours to thecylindrical shape of said vessel to increase the circular flow of thecontaminated fluid mixture entering said vessel.
 15. The apparatus ofclaim 11, wherein said tangential introducing means includes arestricted orifice to increase the velocity of the contaminated fluidentering said vessel.
 16. An apparatus for clarifying a contaminatedfluid mixture containing contaminating fluid, principal liquid andsolids, the apparatus comprising:(a) a substantially vertical elongatedcylindrical vessel wherein said contaminating fluid and solids areseparated from said principal liquid in the contaminated fluid mixture;(b) means for tangentially introducing said contaminated fluid mixtureinto said vessel so as to establish a swirling body of fluid therein,said introducing means extending horizontally into the upper portion ofsaid vessel below an upper surface of said contaminated fluid; (c)aeration means extending horizontally into the lower portion of saidvessel for introducing air, in the form of microfine bubbles, into thecontaminated fluid in the intermediate portion of said vessel such thatthe swirling motion of the contaminated fluid mixture causes saidmicro-fine bubbles to rise to the surface of the contaminated fluidmixture, thereby entrapping and separating the contaminating fluid fromsaid principal liquid and solids in the contaminated fluid mixture; and,(d) means for collecting said contaminating fluid which has risen abovethe surface of the swirling body of the contaminated fluid mixture, saidcollecting means being positioned in the upper portion of said vesselsuch that the top portion thereof is above said tangential introducingmeans, said collecting means comprising:i) a substantially vertical weiror wall portion spaced from said tangential introducing means andextending laterally in said upper portion of said vessel and defining acollecting container having a generally segment shaped cross sectionwith an open top; ii) a bottom portion connected to said vertical wallportion and the inside wall of said vessel, thereby forming saidcontainer open at the top within said upper portion of said vessel; and,iii) an outlet port provided in the wall of said upper portion of saidvessel and in the lower portion of said container, whereby contaminatedfluid is removed from said collecting means.
 17. The apparatus of claim16, wherein said tangential introducing means includes a preliminaryseparation means for producing gas bubbles in the contaminated fluidmixture as it is introduced into said vessel such that the bubblesentrap and separate the contaminating fluid from said principal liquidand solids in the contaminated fluid.
 18. The apparatus of claim 17,wherein said preliminary separation means is a sparging tube mountedwithin said tangential introducing means.
 19. The apparatus of claim 16,wherein said tangential introducing means includes an end portion withinsaid vessel that contours to the cylindrical shape of said vessel toincrease the circular flow of the contaminated fluid mixture enteringsaid vessel.